Cyclopentanopolyhydrophenanthrenes and process of making same



Patented Apr. 11 195 "OFFICE.

CYCLOPENTANOPOLYHYDROPHENAN- THRENES AND PROCESS OF MAKING SAME Tadeu's Reichstein, Basel, Switzerland No Drawing. OriginaP-application February's 1943, Serial No. 474,726. Divided-and this ap-- plication February ;-27, 1946, Serial No. .:65 -0,732-

a .In SwitzerlandApril 25, 1942 It has been found that compounds of the cyclof pentanopolyhydrophenanthrene series contain ing oxygen, or groups including oxygen, in ring C, can be produced by treating compounds. of this series, containing a nuclear double bond in which the carbon atom 11 participates, with agents capable of eliminating this double bond with production of addition compounds, in which an oxidic oxygen. is attached to the carbon atoms 11 and 12 or the carbon atoms 9 and 11 and, if desired, reacting the products obtained with oxidixing and/or reducing agents, or agents which efiect isomerization of an oxide grouping into the keto form. The products obtained .in this way may subsequently be treated with hydrolyzing, esterifying, oxidizing, reducing or halo-. genizing reagents or agents which eliminate hydrohalide, either singly or in combination, in any order of succession.

' The compounds mentioned above which are unsaturated in ring C are obtained, for example, according to the process described in U. S. patent applications No. l33,072, now abandoned, and 435,570 (U. S. Patent No. 2,409,798) from the corresponding compounds containing, for instance in the 12 position, a free or substituted hydroxyl group; or by degradation of the s de chain as described in U. S. Patent No. 2,387,706. The remaining rings of the nucleus are saturated or unsaturated. The. starting products may iurther be substituted in any way, e. g. in the 3, .7 and/or 17 position. The following compounds may for example be used: A -3-hydroxycholenic acid, A -3-keto-cho1enic acid, A 3,7-dihydroxy-cholenic acid, A -3-hydroxycholadienic acicl, A5=5J1I12 3 keto-choladienic acid, A -pregnen-3 ZO-dione, A -'pregnadiene-3,20-dione, A -etiocholene 3,171 jdione, A eetio-choladiene 3,17 -dione, the lower homologues of'the above acids as, for. example,- A -3 hydroxyretio-cholenic acid or A -3- keto-etiocholenic acid or the corresponding nor-' cholenic acid or bisnor-cholenic acid. The corresponding derivatives esterified in the hydroxyl and/or carboxyl groups and analogous compounds unsaturated in the 9,11 position may also be used. r 1 :zThe starting .materials containing 'a' double bond in ring C in which the carbon atom 11 par:

ticipates are treated, according to the present process, with agents capable of forming, with removal of this double bond, addition compounds in 'whichan oxidic oxygen is attached to the carbon. atoms-11 and '12 or the "carbon atoms a and '1 1. "In particular therefore, oxidizing agents e. g. bromacetamide or ,toluene-sulpho-chlora;

mine, may be used instead of the oxidizing agents mentioned, particularly when starting from 11,12 unsaturated compounds. Halo-hydrins obtained can be subsequently converted into oxides by theaction of substances which split off hydrohalide, e. g. alkaline substances. in particular aluminium oxide. In this way oxides are generally obtained which are stereoisomers of those prepared directly by the action of peroxides on the unsaturated starting materials. i

Oxide groups can be split up with reducing agents e. g. with amalgams, with metal alc0- holates or phenolates such as thoseof aluminium or magnesium, in the presence of secondary alco-. hols, with alkali metals and alcohols, with cata lytically activated (e. g. bymetals) hydrogen, or by electrolytic or biochemical -means. Oxide groups may. also be converted directly into keto groups by using the known methods which effect isomerization of an oxide into the keto form,

e. g. with dilute aqueous or alcoholic acids or alkalis, zinc chlorideor concentrated acids such as phosphoric acid.

Halogenatoms which have been introduced, as for examplein the halohydrins, can also be ,removed by means of suitable reducing agents, e. g. zinc and glacial acetic acid. Advantageously, prior to this reduction adjacent free hydroxyl groups which may be present, are converted into keto groups. The oxidizing or equivalent dehy-. drogenating agents suitable for this purpose are well known.

The productsmay subsequently be further .converted in aknown way, by esterification, SfiDOHi': fication;:oxidation-or dehydrogenation, reduction; halogenation, elimination of acid, oracombi nation of' these reactionsiinany order of succession. For-example partially ester-ified' 'glye 0015, e. g. glycol-'xnono-acylates or halo hydrins may be directly converted in known way into ke'e tones, by treatmentwith agents eliminating acid; such? as :fmely. 1 divided metals 5 (in particular zinc) in inert diluents, or with suitablereagents which eliminate hydrohalide. The formation of ketones in this reaction presumably is attributable to the already mentioned isomerlzing ability of ringoxides intermediately formed.

By the present process there may be thus obtained the following intermediate and final products: Compounds of the cyclopentanopolyhydrophenanthrene series (among others saturated ones in which the rings A and B are linked together in cis-position) which contain, instead of the initial double bond in ring .0, a free or esterified hydroxyl group, attached to the carbon atom 11 and a halogen {atom sat thecarbon atom 12, or an oxidic oxygen attached to the carbon atoms 11 and 12, or a .keto .group in ll-position Compounds of this; typehave'been described formerly in the literature as obtained by' transformation and deg'radation of aglucon'es with cardiac activity likedigoxigenin. It has been shown recently that. the original hydroxyl group in ring C of the latter compounds is not located in 11 position,-sothat all'the described corresponding transiormation and de r d products cannot have the claimed constitution with a substituent in ll'eDQSlfiOIl. Saturated compounds of the said configuration in reality were, obtained for the first time according to the presentprocess. Other productsobtained by this process contain at. both thecarbon atom 11 and 'anuclear carbon atom. vicinal, thereto, assub- To 668 mg. of N -cholenic acid methyl-ester M. Pt. 59-61 0. (prepared for example from l 2-hydroxy-cholenic acid methybester, M. Pt. 120-121 C., by saponification, decomposition by heating in vacuo at 240-300 C. and subsequent methylation) is added a solution of "745 mtg-.perbenzoic acid in 40 cc. of chloroform and thewhole allowed to stand for 12 -hours at roomtemperalbum. The chloroform is evaporated off in vacno, the residue dissolved in-ether, the solution washed with sodiumcarbonate solution and water, dried over sodium sulphate and considerably concentrated. 'When pentane is added, crystallization takes'place. After filtering oh. by suction, washing with pentane and drying. 11,12-oxido-cholanic acid methyl-ester, M. Pt. 9'697 C. is obtained. 'On recrystallization from methyl alcohol it melts in a pure condition at 9v7-98 C. Saponification with a solution of potassium carbonate 'inimethyl alcohol gives 11,12- oxido-cholanic acid, M; Pt.'155-'1-57 C.

In an analogous way A 3-acetoxy cholenic acid methyl-ester, M. Pt. 117419 0.,gives11'l;12 oxido-3-acetoxy-cholanic acid methyl-ester. If one starts from an esterified A -3 hy'droxycholenicacid, such as A -3-acetoxy-cholenic acid methyl-ester (obtained for example by re duction of A -3-acetoxy-=l2eketo-cholenic acid "methylrester with hydrazine and sodium eth- Example 2 240.7 mg. of A -3-keto-cholenic acid (obtainable for example from A -3-keto-cholenic acid methyl-ester, M. Pt. 122-124 C., by saponii fication with 2% caustic alkali in methyl alcohol) are dissolved in 6 cc. of pyridine, stable to permanganate. Then 6.50 cc. of N/lO-caustic soda solution are added, so that the solution is Just feeblyalkaline to phenolphthalein. A soluztiDIl or, 102.2 mg. potassium permanganate (1 mol) in 15cc. water is then added in eight portions within a period of 2 hours and the reaction mixture finally allowed to stand for 2% hours. The. precipitate is filtered off and washed with a mixture ofpyri'dine and water, the clear filtrate'acidified with hydrochloric acid while coolingin ice, and the separated precipitate filtered 101T by suction and thoroughly washed with water. This precipitate is then dissolved in ether, the other solution Washed once again with water... dried, concentrated down considerably, and

an excess of di'azomethane added. Afterdmin utes. the solution is workedup in the usual way and a crude product is obtained which is dis solved inpe'troleum ether and chromatographed over 6.3 aluminium oxide. In this way, in addition to unchanged parent material, fractions are obtained which, on recrystallization from ether-petroleum ether mixtures and then from aqueous methyl alcohol, give platelets which' melt at 105-1075 C. after marked sintering;

(concentration 1.372 in methyl alcohol). This substance is a 3 keto 11,12-dihydroxy-cholanic acid methyl-ester.

'Bysplitting oif waterfrom this compound, for example by distillation with zinc dust, a diket ocholanic acid methyl-ester is'obtained. this reaction the '3-keto-1L12-0xide is first formed, which oxide is 'isomerized into the '3,'I1-d iketo compound. Otherwise by mild oxidation or'betcar by dehydrogenation, ior example with a ire tone in presence of a metal alcoholate or phenolate, the 11,12-dihydroxy compound yields the 3,Il,12-triketo-cholanio acid methyl-ester.

Example .3

1.3 g. of A -cholenic acid methyl-ester, Pt. 59-61 C'., are dissolved in 50 cc. of absolute ether, a solution of '1 g. of osmium 'tetroxide-m 50 cc. of absolute ether is added and the'whole allowed to stand for three days at roomtemperature. The dark solution is then concentrated down atfirst on a water bath and thenin vacuol The residue is dissolved in'IO cc. of benzene and 5,0 '00. of alcohol, a hot solution "of 2 g; of potassium hydroxide 'and'Z g. of crystallized sodium sulphitein 12 cc. of water-addeclho't to the sold-- tion obtained, and themixtureboiled for Bhours' under'refiux. '2 cc. ofsaturated -,aqueous saline. with 8 'cc. of'alcohol is then added toithefiltered mixture to produce better separation of the docs culent precipitate and the whole boiled for an-' other hour whereby therbenzene :is allowed to. distil ofi, replacingiit with alcoholisaturated'with sodium chloride. It is then filtered hot and 121510.15 oughly washed out with hot alcol'mlwhichfis saturated with :sodium, chloride.

holsin a vacuum. Hydrochloric :acid'iis added;

.when it is extracted with ether. The ether solution is washed with some water, dried over sodium sulphate, and a solution of diazomethane in ether added until a permanent yellow colouration is obtained. After minutes, it is washed with aqueous hydrochloric acid, sodium carbonate solution and water, dried over sodium sulphate and evaporated down. There remains a light brown residue, which crystallizes after a few hours. 7

The crystals are purified by dissolving in a mixture of benzene and petroleum-ether (1:4)

and filtering the solution througha column of '30 gQaluminium oxide prepared with petroleum (concentration 1.86 in methyl alcohol). The preparation melting at 103-04 C. has an identical specific rotation of [a] =+12.2:1 (concentration 1.973 in methyl alcohol).

Both preparations prove not to be identical with a presumably stereoisomeric 11,12-dihydroxy-cholanic acid methyl-ester, which is obtained from A -cholenic acid by treatment with potassium permanganate and subsequent methylation in an analogous manner to that described in Example 2.

v3() mg. of 11,12-dihydroxy-cholanic acid methyl-ester M. Pt. 83.5 C. or 103-104 C. are boiled for 15 minutes with a solution of 8 mg. potassium hydroxide in 0.5 cc. methyl alcohol. Some water is then added, the methyl alcohol removed in vacuo, and the remaining mixture extracted with ether after the addition of hydrochloric acid. The ether solution is washed with water, dried over sodium sulphate, considerably concentrated, and pentane added. The

free 11,12-dihydroxy-cholanic acid thus obtained crystallizes in small needles, which collect in aggregates, having a M. Pt. 211-214 C.

.100 mg. of 11,12-dihydroxy-cholanic acid methyl-ester, M. Pt. 83-85 C., or 103-104 C. are boiled with 0.6 cc. of acetic anhydride and 1 cc. of pyridine for 8 hours under reflux. The mixture is then evaporated down in vacuo, the residue dissolved in ether, the ether solution washed with hydrochloric acid, sodium carbonate solu-- tion and water, dried with sodium sulphate and evaporated down. The residue gives, when recrystallized from methyl alcohol, 11,12-diacetoxy-cholanic acid methyl-ester. in colourless rods, M. Pt. IDS-110 C., [a]D =+1.5:t1 (concentration 1.94 in acetone). By heating this compound there are used as starting materials corresponding derivatives, containing an additional hydroxyl, acyloxy or keto group in 3-position of the cholene or etiocholene nucleus, correspondingly substituted products of the said series are obtained.

Example 4 300 mg. of A -cholenic acid methyl-ester are dissolved in 60 cc. of acetone, a solution of 222 mg. bromacetamide (2 mols) is added and the whole allowed to stand for 16 hours at room tem-, perature. The acetone is removed in vacuo, water added to the residueand the whole extracted with ether. The ether solution is washed with sodium carbonate solution and water, dried over sodium sulphate and evaporated down. The residue is treated in a column as used for chromatography by aluminium oxide. At first a dibromide, M. Pt. 101.5-1035 C. is eluted with petroleum ether. The fractions extracted afterwards with petroleum ether and a mixture of petroleum ether and benzene (3:7) give, on recrystallization from aqueous methyl alcohol, the a-oxide, M. Pt. 64.5-65.5 C., which has the formula:

COOCH:

Further eluates probably contain the 9,11-dibromo-12-hydroxy-cholanic acid methyl-ester, as debromination of this product with zinc dust and subsequent oxidation with chromic acid yield the A -l2-keto-cholenic acid methyl-ester.

The same a-OXldG can also be obtained by treating the crude product of the bromacetamide reaction with zinc dust or other agents which eliminate hydrohalide.

86 mg. of the a-OXide described are dissolved in 3 cc. of methyl alcohol, the quantity of Raney catalyst obtained from 300 mg. of alloy is added, and hydrogenation performed during 2 hours at C. and atmospheres in a rotating autoclave. After filtration the solution is evaporated down, the residue dissolved in ether and the ether solution washed with sodium carbonate solution and water, dried over sodium sulphate and evaporated down. The residue is chromatographed over aluminium oxide. The fractions extracted with petroleum ether crystallize from methyl alcohol and thus give a small quantity of cholanic acid methyl-ester. The 11-hydroxycholanic acid methyl-ester, M. Pt. 87-88 .C. is eluted with mixtures of benzene and petroleumether in the concentrations 1:9 till 3:7. It has the formula:

CH; H

".insteadtof ashydrogenati'on of: the'a oxi'de with subsequent oxidation, :also an isomerization may be performed directly to .the ketone in known manner. The latterm'ay afterwards he reduced to the. alcohol.

Example 500 mg of A -3-keto-cholenic acid methylester, M. Pt..l'20-I22 C., are dissolved in 40 cc. of.;acetone, a solution of1350 .mg. of bromacetamide (2 mols) in .10 cc. of water is added and the wholeallowed to stand for 16 hours at room temperature. After the addition of water, the acetone is removed. in vacuo and the residue extrac'tedtwith ether. The ether solution is washed with diluteisodium carbonate solution and water dried over sodium sulphate. and evaporated down. The residue is treated according to the chromatographic. method with 20 'g. of aluminium oxide. The eluates with benzene and benzenee ther mixturesCSUzl) give the 3-'keto-11',12-diblfonhcholanic acid methyl-ester in colourless needles, which melt after recrystallization from ether-petroleum ether, at 136-138 C. by debromination they yield'the parent substance. Further fractions extracted with benzene-ether mixtures of increasing ether content, and with pure ether, give thell,12-a oxido-3-keto-cholanic acid methyl-ester which melts, .on recrystallization from petroleum ether, at 122-124 C. It has the formula:

The" further fractions'eluted with ether-methyl alcohol (9:1) give on oxidation with chromic acid and d'ebromination with zinc dust, A -3,12- dike'to cholenic acid methyl-ester.

I The oxide described yields, on hydrogenation, 'a'reaction product which forms, after acetylation with acetic anhydride and pyridine at room temliterature, in addition to the 3-acetoxy-11-hydroxy-cholanic acid methyl-ester, M. Pt. 146- 148' 'C., the ester which is "stereoisomeric in 3 position andshows a M. Pt. of 141-142 (3., and a specific rotation Eu-]n =+50 (acetone).

' Instead of using A -3-ketocholenic acid methyl-ester as a'starting material, also A -3- acetoxy-eti'o-cholenic acid imethyl-ester may be converted to the corresponding 11,12-oxide which is subsequently reduced to the 'll-hydroxy com.- pound' or isomerized to the 3-keto compound. The 1 conversion of the A 3-acetoxy-etiocholenic acid methyl-ester to the 11,1'2-oxide is performed as follows:

215 mg. of A -3-acetoxy etio-cholenic acid methyl-ester, melting pointQQ-IOO" C. (obtained as described in U. 5:. Patent No. 2,387,706), are dissolved in 15 cc. acetone. To this solution one of 150 mg. of bromoacetamideinu cc. of water is added andzzthevwhol allowed'to stand for 16 hours at room temperature. It is then diluted with water, the acetone evaporated off in vacuo and the residue extracted with ether. The ether solution is washed with sodium carbonate solution :and water; dried 'over'isodium sulphate and evaporateddown. Theresiiiualcrude product is 8 recrystallized-from ether; It consists of a halohydrin', melting point 218-222" C.', of the formula.

This .halohydrin is converted by treatment withaluminium oxide. into the a-oxide, whichhas the formula.

t COOCH:

AcO-

and on isomerization yields the ll-keto coinpound with the formula C Ha Aims.-

This application is a division of my application Serial No. 474,726, filed February 4, 1943 (now U. S. Pat. No. 2,403,683)

'What I claim is: p

1. A cyclopentanopolyhydrophenanthrene containing an oxidic oxygen attached to the carbon atoms '11 and. 12.

2. A cyclopentanopolyhydrophenanthrene containing an oxidic oxygen attached to the. carbon atomsll and 12, and at the carbon atom '3 a member of the group consisting of an acyloxy group and a ketonic oxygen.

3". A cholane containing an oxidic oxygen/attached to the carbon atoms 11 .and "12. v

'4. A cholane containing-an oxidic oxygen'attachedto the carbon atomsll 'and 12, and "at the carbon atom 3' amember of the group con sisting of an acyloxy group and a ketonic' oxygen.

5. In a process for the manufacture 'ofa cyclopentanopolyhydrophenanthrene containing 'a keto-groupin ll-position, starting from 'acycl'og pentanopolyhydljophenanthrene COUCH:

containing a I doublebond between'th'e carbon "atomsll; and

9 10 12, the steps comprising acting on an unsaturated A -cyclopentanopolyhydrophenanthrene REFERENCES CITED with a hypohalogenous acid, resulting in the formation of a 12-halogeno-1l-hydroxy-cyclofile of P pentanopolyhydrophenanthrene, and treating the product with a. dehydrohalogenating agent whereby hydrohalogenic acid is split ofi and an um r UNITED STATES PATENTS Name Date 11,12-oxido compound is formed. 2,265,143 Butenandt 9, 19 TADEUS REICHSTEIN 2,323,277 Miescher June 29, 1943 The following references are of record in the 

5. IN A PROCESS FOR THE MANUFACTURE OF A CYLCOPENTANOPOLYHYDROPHENANTHRENE CONTAINING A KETO-GROUP IN 11-POSITION, STARTING FROM A CYCLOPENTANOPOLYHYDROPHENANTHRENE CONTAINING A DOUBLE BOND BETWEEN THE CARBON ATOMS 11 AND 12, THE STEPS COMPRISING ACTING ON AN UNSATURATED $11,12-CYCLOPENTANOPOLYHYDROPHENANTHRENE WITH A HYPOHALOGENOUS ACID, RESULTING IN THE FORMATION OF A 12-HALOGENO-11-HYDROXY-CYCLOPENTANOPOLYHYDROPHENANTHRENE, AND TREATING THE PRODUCT WITH A DEHYDROHALOGENATING AGENT WHEREBY HYDROHALOGENIC ACID IS SPLIT OFF AND AN 11,12-OXIDO COMPOUND IS FORMED. 